High-sensitivity piezoresistive sensors based on functionalized carbon nanotube/TPU composite for human motion detection

Abstract

Piezoresistive sensors are widely used in a variety of fields due to their high sensitivity, low cost, and ease of integration. As technology advances, new materials and structures are designed to continue driving the improvement of piezoresistive sensor performance and the expansion of their fields of application. A unique functionalized multi-walled carbon nanotube (MWNTs-g-TPU) with thermoplastic polyurethane (TPU) chains was prepared by chemical grafting in this study. Conductive composites with piezoresistive properties were prepared by the solution blending method with TPU as the polymer matrix and MWNTs-g-TPU as the reinforcing filler. MWNTs-g-TPU interacts more strongly with TPU than non-functionalized MWNTs, significantly improving the mechanical, electrical, and piezoresistive properties of MWNTs-g-TPU/TPU composites. A sensor was fabricated using a 5.0 wt% MWNTs-g-TPU/TPU composite, demonstrating high sensitivity to external pressure. The composite material exhibited a stable piezoresistive response after multiple cycles, which indicates its great potential in the piezoresistive sensor field.